WO2000059767A1

WO2000059767A1 - Steering device for vehicles

Info

Publication number: WO2000059767A1
Application number: PCT/EP2000/002839
Authority: WO
Inventors: Holger Lüthje; Rainer Kist; Thomas Reul
Original assignee: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.; Philipp Walter Industrievertretungen
Priority date: 1999-04-01
Filing date: 2000-03-30
Publication date: 2000-10-12
Also published as: ATE234217T1; EP1165358B1; EP1165358A1; US20100179727A1; US8209088B2; DE19915105A1; ES2189754T3; DE50001445D1

Abstract

The invention relates to a steering device for vehicles comprising a steering shaft (20), a sensor (35) provided for determining the movement of said steering shaft, and a circuit (40) provided for evaluating the measuring signals of the sensor (35). In addition, coded microstructures (31) are provided on the steering shaft (20) and/or on a device that is connected to the steering shaft in a non-positive manner. A sensor (35) detects the microstructures (31) and outputs associated measuring signals. The measuring signals of the sensor (35) are fed to an electronic circuit (40) which outputs electronic signals for controlling the steering.

Description

Steering device for vehicles

The invention relates to a steering device for vehicles, with a steering shaft, a sensor for determining the steering shaft movement and a circuit for evaluating the measurement signals of the sensor.

Steering of vehicles can be implemented in different ways. Rack and pinion steering is used particularly often. A driver exerts a torque on a steering column via a steering wheel. A direct power transmission then takes place via a pinion, i.e. a gear wheel, to a rack. The longitudinal movement of this rack is also the longitudinal movement of a steering shaft in or on which this rack is introduced. The steering shaft in turn moves the steering linkage with the vehicle wheels arranged on it in this way.

In order to support the direct power transmission by the driver, it is also known in hydraulic power steering systems to provide a pressure chamber in which a piston runs, which is firmly connected to the steering shaft. By controlling the pressure in the pressure chamber filled with hydraulic oil, the piston can be moved and in this way the steering linkage can be moved in addition to the power transmission by the driver. Alternatively, the drive of the pinion can also be supported by an electric motor.

In order to be able to implement these different forms of support, it is of course desirable to have a measurement signal that correlates with the state of the steering. This signal could then take over for a suitable control for steering support, for power steering and similar purposes and also enable self-regulating systems. In addition to the control of the servo device, supporting measures to optimize the steering and damping behavior of motor vehicles or a simultaneous control of all four wheels and other intelligent steering systems would also have to be taken into account. There are already various proposals for obtaining a signal that correlates with the state of the steering.

For example, DE 40 29 764 A1 proposes to arrange a length measuring device between the steering wheel and the front axle which responds to the displacement of the rack. Inductive or ohmic devices are proposed for this length measuring device. A concept with two magnetoresistive sensors is known from EP 0 410 583 B1. Here the magnetic coupling is changed when the steering shaft moves, thus enabling a position determination. However, the steering shaft must be geometrically modified and additionally provided with a groove, which in addition to costs also leads to a certain susceptibility to faults. EP 0 376 456 B1 also works with a magnet. The magnet arranged on the steering shaft is enclosed by an induction coil. An induction change can be assigned to a path change.

Steering angle sensors are known from DE 197 03 903 A1 and DE 197 52 346 A1, which work with magnetic field sensors, so-called Hall sensors.

These known proposals have the disadvantage that the measurement only allows limited accuracy. It is also problematic that these are relative measurements, so that measurement errors add up over time. These suggestions are therefore not practical for use with intelligent steering systems.

From DE 37 03 591 C2 it is known to carry out a measurement of the angle of rotation of this steering column in a rack and pinion steering at the end of the steering column by applying an induction coil or a piezo force measuring cell accordingly. However, the end of the steering column also carries the power transmission to the rack and is both structurally narrow and unfavorable for measurements, especially since many faults can occur here. In contrast, the object of the invention is to propose a steering device in which a signal which correlates with the state of the steering can be removed and which is better suited for controlling such intelligent steering systems.

This object is achieved in that encoded microstructures are provided on the steering shaft and / or in a device that is non-positively connected to the steering shaft, that a sensor is provided that detects the microstructures and emits associated measurement signals and that an electronic circuit is provided that measures the measurement signals are supplied by the sensor and emits soft electronic signals for controlling the steering.

With this invention, a steering device for vehicles is proposed that allows an absolute position measurement. The disadvantages of the prior art no longer exist. The steering device according to the invention is more precise and provides reproducible measurement signals. Regulation and / or control of the movement of the steering shaft is possible, in particular for intelligent steering systems.

The result is a combination of modern surface technologies with microstructuring processes on the one hand and a high-resolution sensor, i.e. a detection system, with a corresponding electronic circuit on the other. Micro structures are understood to mean structures with dimensions in the micrometer range.

“Detect” is understood to mean, in particular, methods in which contactless detection takes place, preferably optically or magnetically. However, other detection options are also considered, which read out, scan, feel or otherwise recognize.

The invention enables a fast, high-resolution and reliable absolute determination of the position of the steering shaft, with a resolution in the lower micrometer range. Falsification or interference by electromagnetic fields or in the area of the steering does not take place or is immaterial. The invention can be successfully used in particular in modern, so-called intelligent steering systems.

It is possible to equip the steering shaft itself with the micro structures. The disadvantage here would be the difficult handling of the entire steering shaft during fitting. In order to circumvent this, replaceable, smaller elements, for example in the form of a rod, which can be non-positively connected to the steering shaft, could be appropriately equipped and then used.

The microstructures are advantageously designed in such a way that they contain a suitable coding that allows the position of the steering shaft to be determined absolutely.

The microstructures are preferably detected using optical scanning methods, in particular using elements of microsystem technology. Microsystem technology means the areas of microstructure technology, micro-optics and fiber optics. Microlenses with diameters down to approx. 10 μm and focal lengths in the same order of magnitude can be used. When using glass or other fibers and very small diameters, the microlenses can be fixed directly on the face of the fiber. The overall system can have Y branches and is integrated with individual modules to form a compact microsystem. If necessary, the modules can be spatially separated via the optical fibers, for example in order to be able to optimally operate optoelectronic components and the evaluation electronics in areas of low temperature.

Advantageously, tribologically suitable layer systems are applied to the steering shaft or to a linear device connected to it without play, referred to as a device or measuring device. This can be done using thin-film processes that have proven themselves in other technical fields. Using high-resolution structuring and etching processes, special Microstructures created. The microstructures are designed so that they can also be read out with the sensors.

For example, the optical contrast, that is the difference in reflectivity, of the microstructures to the underlying surface of the steering shaft is modified in such a way that the patterns can be optically recognized with the aid of miniaturized fiber-optical systems. Another example is the implementation of the microstructures as a reflection hologram, the coding being carried out similarly to the preceding example (segment by segment) and the reading being carried out by a suitable miniaturized optical system. The functional layer can be crystalline or amorphous and the hologram can be written in phase or angle-coded. The hologram can be functional for one frequency range (monochromatic) or for several frequency ranges (colored), the information can be written in digital or analog (in the hologram).

Instead of or in addition to optical sensors or optically detectable microstructures, other physical methods can also be used. The microstructures can also be formed in magnetic layers, for example CoSm or NdFeB. Magnetic sensors that would otherwise be used in data storage technology could then be used as sensors.

The microstructures are produced on the steering shaft or on the device which is non-positively connected to the steering shaft in the form of incremental markings. Tribologically optimized layer systems using high-resolution lithographic or laser technology methods suitable for three-dimensional applications are preferred. Photolithographic, electron-lithographic, X-ray lithographic and / or ion-lithographic processes can be used as the lithographic process.

Multi-layer or composite structures can also be used. The patterns are preferably realized in micrometer dimensions. In conjunction with a suitable sensory detection system, the layer systems allow an absolute determination of the current position, with an accuracy of a few micrometers.

In an advantageous embodiment of the invention, two mutually complementary and parallel patterns are provided with a suitable coding, for example a bit coding. In one embodiment, the marking structure consists of stripes that can be optically distinguished by reflection, the stripe patterns containing binary UO codes.

As a result, the position measuring system, which can be fully integrated into the steering gear, can recognize the current absolute position of the steering due to the bit coding in every operating phase.

Different patterns are possible. For example, a dual code, a gray code or even step codes, which are known as such from relevant mathematical processes, can be used.

Optical sensors, in particular fiber-optic double sensors, are particularly preferably used for scanning the markings and the microstructures. Multiple sensors, especially in the form of an array, are also possible.

The microstructures are produced in a preferably used method using thin-film techniques. PVD (Physical Vapor Deposition) and / or CVD (Chemical Vapor Deposition) techniques are advantageously used as thin-film techniques. As mentioned, the structure is structured using lithographic techniques.

The microstructures can also be produced by dry etching processes and / or wet chemical etching processes. Alternatively, production using laser beam techniques, for example direct writing laser ablation processes and / or laser lithographic processes and / or direct-acting, mask-related laser structuring processes, is possible.

The microstructures are preferably constructed from tribological hard material layer systems. Single layers or multilayer layers come into consideration. These preferably consist of titanium nitride (TiN) and / or titanium aluminum nitride (TiAIN) and / or titanium carbonitride (TiCN) layers and / or aluminum oxide layers and / or amorphous diamond-like layers

Hydrocarbon layers with or without metal doping and / or amorphous diamond-like carbon layers with or without metal doping and / or amorphous CN layers and / or cubic boron nitride layers and / or diamond layers.

Exemplary embodiments of the invention are described in more detail below with reference to the drawings. Show it:

Figure 1 shows a schematic section through essential elements of an embodiment of a steering device according to the invention;

Figure 2 shows an alternative embodiment to Figure 1;

Figure 3 is a schematic representation of a microsystem sensor system for an embodiment of the steering device according to the invention;

FIG. 4 shows a detailed illustration of an element from FIG. 3;

FIG. 5 shows a detailed illustration of an alternative embodiment of this element from FIG. 3;

FIG. 6 shows a detailed illustration of another element from FIG. 3;

FIG. 7 shows an example of a microstructure;

Figure 8 shows an alternative embodiment of Figure 7;

Figure 9 shows another alternative embodiment of Figure 7;

FIG. 10 shows a schematic section through a microstructure;

FIG. 11 shows the embodiment from FIG. 10 after a possible further processing cut;

Figure 12 is a schematic section through another embodiment similar to Figure 10;

Figure 13 is a schematic section through a third embodiment similar to Figure 10; FIG. 14 shows the embodiment from FIG. 13 after a possible further processing cut; and

Figure 15 is a schematic representation of an embodiment of a sensor.

The embodiment of a steering device according to the invention shown in Figure 1 has a mounting block 10, in the interior of which there is a pressure chamber n, which is largely filled with hydraulic oil 12. The hydraulic oil 12 is under a pressure p. The assembly block 10 is shown here purely schematically; here it assumes an essentially cylindrical design, with essential parts of the assembly block 10 still extending to the right from FIG. 1.

The steering shaft 20 extends approximately along the cylinder axis of the mounting block 10. The steering shaft 20 thus extends through the pressure chamber 11 with the hydraulic oil 12. The steering shaft 20 is provided with a toothed rack 21, which is indicated here in FIG. 1 by corresponding tooth markings. The rack 21 is driven by a pinion 22. This pinion is connected to the steering of a vehicle, not shown. If the steering wheel of a passenger vehicle is turned, for example, the corresponding torque is transmitted via the pinion 22 to the rack 21 and with it moves the entire steering shaft 20 along the axis through the mounting block 10.

A piston 23 is also seated on the steering shaft 20 in a non-positive connection. This piston 23 is arranged within the pressure chamber 11 and thus within the hydraulic oil 12, while the pinion 22 and the toothed rack 21 are located outside the pressure chamber 11.

The steering shaft 20 thus passes through the wall of the pressure chamber 1 at two points. Both points are sealed by means of seals 24, preferably by means of Viton seals. The piston 23 also moves longitudinally with the steering shaft 20 due to its positive connection. It fills the entire cross section of the pressure chamber 11. As a result, the piston 23 and thus the piston 23 can also be changed by changes in pressure Steering shaft 20 are moved. This is also a common method to increase the forces exerted by the user of the vehicle through the pinion 22.

Suitable diameters of steering shafts 20 are approximately 20 to 40 mm, suitable diameters of pressure chambers 11 approximately 40 to 70 mm, steering shafts 20 have lengths of the order of 800 mm, for example, the length of the pressure chamber 11 can be 200 to 400 mm, for example.

Of course, entirely different size dimensions are suitable, depending on the requirements of the steering device.

A mounting hole 13 is also made in the mounting block 10 outside the pressure chamber 11. This mounting hole 13 extends from the outer wall of the mounting block 10 to the through hole in which the steering shaft 20 is located. A sensor 35 is located in this mounting hole 13. This sensor 35 can, for example, in the. End of a fiber optic sensor system exist.

In this area in particular, the steering shaft 20 is provided with a marking 30 on its outside. The marking 30 consists of microstructures 31 which are arranged on the top of the steering shaft 20. These microstructures 31 are coded in the axial direction of the steering shaft 20 so that when the steering shaft 20 moves longitudinally relative to the mounting block 10, different bit patterns pass under the sensor 35. The signals from the sensor 35 are fed to an electronic circuit 40 (not shown in more detail in FIG. 1). The electronic circuit 40 can then output a corresponding absolute value determination of the position of the steering shaft 20 in relation to the mounting block 10 from the readings of the sensor 35.

In addition to the longitudinal movement of the steering shaft 20, further movements of the steering shaft are of no interest for the steering. Therefore, nothing about any rotations of the steering shaft 20 is shown in FIG. 1. Here are all the variations conceivable that ensure a corresponding running of the pinion 22 on the rack 21.

FIG. 2 shows another alternative embodiment with a representation similar to that shown in FIG. 1.

The mounting block 10 with the pressure chamber 11 and the hydraulic oil 12 can also be seen here. The steering shaft 20 with the rack 21 runs through the mounting block 10 and the pressure chamber n. The pinion 22 also drives the rack 21 here. On the steering shaft 20 there is also a piston 23 which can run within the pressure chamber 11.

In contrast to FIG. 1, not only one mounting hole 13 is provided here, but also another mounting hole 14 outside the pressure chamber 11.

This difference also enables two sensors 35 and 36 to be arranged. This makes it possible to read out redundant or complementary or else double-coded microstructures 31 of the marking 30. The sensors 35 and 36 are preferably fiber-optic reflection sensors. The light source of the reflection sensors is formed by light-emitting diodes (LEDs), the LEDs being spectrally matched to the hydraulic oil 12 used in the pressure chamber 11. Pentosin can preferably be used as hydraulic oil 12.

The pressure p of the hydraulic oil 12 in the pressure chamber 11 is regulated via valves in a valve control housing (not shown).

The steering shaft 20 is sealed at its passage openings into the pressure chamber 11 and out of the pressure chamber 11 by seals 24, which are in particular Viton seals. The steering shaft 20 has a center position which corresponds to the steering angle 0 °. This is indicated in Figure 2 as the center position X ₀ . Movement to the right or left then takes place in the direction of the steering shaft position + X (right) or in the direction -X (left). These respective end positions correspond to a linear stroke, which can typically be ± 75 mm. Depending on the vehicle type, this results in different steering angles. In individual cases, depending on the vehicle type, this linear stroke can also be smaller, for example ± 50 mm.

The two mounting holes 13 and 14 are arranged here outside the pressure chamber 11, so that the two individual sensors 35 and 36 are also arranged outside. It is also possible to provide an integrated pair of sensors here.

In another embodiment, the sensor or sensors 35 and 36 can also be positioned within the pressure chamber 11. The sensor can then, for example, be at a distance from the steering shaft 20, that is, as an optical sensor, it can detect the data of the steering shaft 20 by means of the hydraulic oil 12.

This makes it possible for him, in addition to reading the microstructures 31 of the marking 30 on the steering shaft 20, to provide a statement about the turbidity of the hydraulic oil 12 in the pressure chamber 11. This statement can be used as a criterion for the replacement of the hydraulic oil 12. Depending on the turbidity and spectral absorption of the hydraulic oil 12, a suitable transmission wavelength is selected for the optical sensor 35. Such a system also works in the event of contamination by abrasion particles or an oil film and, for safety reasons, preferably has corresponding redundancy, fault tolerance and azimuth tolerance.

The sensors can be fiber-optic sensors with two individual fibers, as is indicated in FIG. 2, these (not shown) can be parallel to one another and inclined in order to receive incoming and reflected light. However, it is also conceivable to use fiber-optic refiection sensors in a Y structure or to take into account arrangements with fiber rows or fiber bundles. The sensor or sensors 35 and 36 or also a sensor system 37 (see for such a system FIG. 3) are used as transmitters or as receivers and can be coupled directly to the fiber using, in particular, temperature-resistant construction and connection technology. Alternatively, they can also be arranged via a feed fiber that is located in an area with a lower temperature. In a further embodiment, the sensor module is assembled as a compact, miniaturized (microtechnical) module for easier installation and installed in the system.

In another embodiment, not shown, to increase the reliability or the interference immunity, it is additionally provided that two sensors 35 are placed azimuthally next to one another. These two sensors then scan two mutually complementary bit patterns, both of which are implemented as thin-film technology, parallel markings 30 with corresponding microstructures 31.

FIG. 3 shows a schematic representation of an embodiment of a marking 30 with microstructures 31. The steering shaft 20 is shown here purely schematically as a section; it extends parallel to the indicated x-direction.

A sensor system with an array of fiber optic Y branches 38 can also be seen. The sensor system 37 has a module A for generating and coupling the light 51 into the input or coupling fibers 39 of the fiber optic Y branch 38.

A module B with an array of lenses 52, in particular microlenses, arranged in the y direction is also provided for generating parallel output light beams. The output light bundles 53 fall on the microstructures 31 of the marking 30 on the steering shaft 20. These microstructures 31 form a sequence of sequences. A position-specific selective retroreflection takes place. The retro-reflecting light again passes through the lenses 52 into the fibers of the module B and from there to a module C for decoupling and detection of the retro-reflected light 55 and leaving the fiber-optic Y-branch 38.

In Figure 3 is also

± x the axial direction, ie the direction of movement of the steering shaft;

± y the azimuthal direction, ie the direction in which the position-specific bit pattern is arranged; and

z the installation direction of the sensor system.

The coordinates x and z are orthogonal to each other; the coordinate z points in the direction of the tangent orthogonal to x and z to the surface of the steering shaft 20.

FIG. 4 shows a detail from FIG. 3, namely a first version of a transmission and coupling module A with a single source 51, single lens 52 and fiber bundles made of coupling fibers 39 of the Y branch 38.

FIG. 5 shows, as an alternative to FIG. 4, another version of a transmission and coupling module A with an array of lenses 52. The fibers are bundled and then separated again as coupling fibers 39 of the Y-branch 38.

FIG. 6 shows another detail from FIG. 3, namely an embodiment of a decoupling, reception and evaluation module C with coupling fibers 54 bundled in places, an array of lenses 52, detector line 56, the electronic circuit 40 with the evaluation electronics and output signal 60 with the " Position of the steering shaft ".

FIG. 7 shows an 8-bit coding in the radial direction and periodic position measuring marks in the axial direction. FIG. 8 shows an arrangement example of blocks with individual codings.

FIG. 9 shows an example of the arrangement of different structural sequences and a lead structure with periodic division for finding the lane with azimuthal displacement.

FIGS. 10 to 14 show exemplary embodiments for possible manufacturing processes for the microstructures 31. A coded pattern is generated on a base body 81, which can also be the steering shaft 20 or another non-positively coupled device with the steering shaft 20. For a variant in which the detection means are to be optically blanked out of the pattern, the base body 81 is treated with a focused laser beam on the surface in such a way that laser-ablative processes at the point of action lead to ablation and thus permanent markings (see FIG. 10).

Eximer lasers are preferably used for this because of the high resolution. The pattern created in this way can then be covered with a friction and wear-reducing layer. This is shown in Figure 11. A metal-doped amorphous hydrocarbon layer, which is applied in a thickness between 0.5 μm and 5 μm by means of known plasma-assisted PACVD processes (magnetron sputtering processes with substrate bias and a hydrocarbon gas, preferably C ₂ H ₂ ), is so outstandingly suitable as such a covering layer in the area of the steering shaft . Titanium or tungsten is preferably used as the doping metal for this application. The metal-doped amorphous hydrocarbon layer is produced, for example, using a large-scale sputtering system from Leybold of the Tritec 1000 type, with two tungsten targets being installed. The system has a rotation holder that can accommodate up to 20 steering shafts, depending on the equipment. After the usual pumping process, which pumps the chamber down to approx. 10 ^"5 hPa, argon is let in up to a pressure of 3 x 10 ^{" 3} hPa and the substrates are cleaned at 100 to 300 V bias potential by ion bombardment on the surface. The targets are sputtered at around 6 KW. Without interrupting the plasma, the target covers are opened and C ₂ H _{2 is} added successively a graded layer of tungsten-doped hydrocarbon is formed for the process. The C ₂ H ₂ gas flow is adjusted after a few minutes so that the ratio of tungsten to carbon in the layer corresponds to 5 to 10 at%. During the production of the metal-doped amorphous hydrocarbon layer, the substrates are coupled with a bias potential between 100 and 300 V, preferably 200 V. Under these conditions, a layer thickness of 1 μm is applied in 0.5 hour.

FIGS. 12 to 14 show further possible solutions that describe the use of a structured layer. The layer structure can serve for different sensor principles. In the case of optical detection, the layer structures have, for example, a suitable contrast (areas or edge contrast) to the surrounding surface. However, the layer structure can also be produced from a magnetic material and read out with the aid of a magnetic sensor or a magnetic sensor matrix, in which case a magnetic layer, preferably made of CoSm or FeSi or NdFeB with and without additives, is used.

The steering shaft 20 or the base body 81 is coated in a vacuum process with in this case two layers 83, 84, the lower layer 23 or a metal-doped amorphous hydrocarbon layer onto which a TiN layer is deposited. The thickness of the upper layer 84 is approximately 0.5 μm. TiN is preferably used in combination with a Ti-doped hydrocarbon layer. The ethyne is only exchanged for nitrogen, again without interrupting the plasma. The structuring of the layer 84 takes place photolithographically in that the coated steering shaft 20 is coated with a photoresist. The thickness is approximately 2.5 μm. The patterns are then generated over a large area on the steering shaft using a mask.

After resist development, the TiN layer 84 is removed wet-chemically using known etchants where there are no photoresist patterns. The patterns can also be sunk, that is to say made planar, as shown in FIG. In this case, the steering shaft 20 is coated with, for example, a W-doped amorphous hydrocarbon layer 85 and then a photoresist pattern is formed thereon. With the help of the photoresist masking, a recess of 0.2-1.0 μm is then etched into the W-doped amorphous hydrocarbon layer in a reactive plasma etching process (etching gases Ar / SF ₆ ). While maintaining the photoresist mask, the depression is then replenished by sputtering of, for example, TiN. The surface is also microscopically smooth.

A further embodiment is contained in FIG. 14, where a tribologically optimized layer 86 is applied for the previously described substructure. In this case, layer materials that do not necessarily have good tribological properties can also be used for pattern generation.

An embodiment of a sensor 35 is shown in FIG. It is a magnetic sensor. It consists of a line-like arrangement of magnetic sensors that can read a magnetic structure, for example in an 8-bit code. The pole structures of the read head are shown, the operational reliability being improved and the number of encodings being increased by using a second line. The sensor 35 can be produced, for example, from known magnetoresistive or inductive single sensors, which are also produced in known thin-film techniques. In order to ensure a minimum distance from the magnetic microstructures on the steering shaft 20, the pole structures of the reading sensors are arranged on a circular arc that is adapted to the diameter of the steering shaft 20.

Reference list

Assembly block

Pressure chamber

Hydraulic oil

Mounting hole

Steering shaft

Rack

pinion

piston

poetry

mark

Microstructures

sensor

Sensor system

38 Y-branch

Coupling fiber

electronic switch

source

lens

Output light beam

Decoupling fibers

light

Detector line

Output signal 81 basic body

82 layer

83 layer

84 layer 85 layer

86 layer

A module

B module C module

P pressure

Xo center position

+ X steering shaft position to the right -X steering shaft position to the left y azimuthal direction z installation direction of the sensor

Claims

Patent claims

1. Steering device for vehicles, with a steering shaft (20), a sensor (35) for detecting the steering shaft movement and a circuit (40) for

Evaluation of the measurement signals of the sensor (35), characterized in that coded microstructures (31) are provided on the steering shaft (20) and/or a device non-positively connected to the steering shaft, and a sensor (35) is provided which detects the microstructures ( 31) detects and emits associated measurement signals and that an electronic circuit (40) is provided to which the measurement signals of the sensor (35) are supplied and which emits electronic signals for control.

2. Steering device according to claim, characterized in that the microstructures (31) form a series of sequences which are arranged in the axial direction on the steering shaft (20) and / or the device non-positively connected to it.

3. Steering device according to claim 2, characterized in that each sequence consists of multiple structures and / or individual structures which are spatially arranged in the azimuthal and / or axial direction and which contain an individual or block-wise coding.

4. Steering device according to claim 2 or 3, characterized in that the sequences contain bit coding.

5. Steering device according to one of claims 2 to 4, characterized in that several sequences are combined into a block, the blocks being distinguishable from one another by coding.

6. Steering device according to one of claims 2 to 5, characterized in that the sequences arranged in the axial direction are present several times in parallel offset over the circumference of the steering shaft (20) and / or the device in a redundant design.

7. Steering device according to one of the preceding claims, characterized in that the microstructures (31) are designed to be complementary.

8. Steering device according to one of the preceding claims, characterized in that the smallest details of the microstructures (31) have lateral dimensions of 5 nm to 5 mm.

9. Steering device according to claim 8, characterized in that the smallest details of the microstructures (31) have lateral dimensions of 1 μm to 1 mm.

10. Steering device according to one of the preceding claims, characterized in that the microstructures (31) have a thickness of 5 nm to 1 mm.

11. Steering device according to claim 10, characterized in that the microstructures (31) have a thickness of 100 nm to 100 μm.

2. Steering device according to one of the preceding claims, characterized in that the microstructures (31) have a flat surface and are leveled using planarization technology.

13. Steering device according to one of the preceding claims, characterized in that the microstructures are constructed from tribological hard material layer systems or are covered with them.

14. Steering device according to claim 13, characterized in that the hard material layer systems single layers or multi-layer layers made of TiN and / or TiAIN and / or TiCN layers and / or aluminum oxide layers and / or amorphous diamond-like hydrocarbon layers with and without metal doping and / or amorphous CN Layers and/or cubic boron nitride layers and/or diamond layers are.

15. Steering device according to one of the preceding claims, characterized in that the sensors (35) are arranged in the form of a row and / or an array.

16. Steering device according to one of the preceding claims, characterized in that the sensors (35) are optical sensors.

17. Steering device according to claim 16, characterized in that the sensors (35) are optical fiber optic sensors.

18. Steering device according to claims 17, characterized in that the sensors (35) are fiber-optic double or multiple sensors.

19. Steering device according to one of claims 16 to 18, characterized in that the microstructures are designed as a reflection hologram.

20. Steering device according to one of claims 1 to 15, characterized in that the sensors (35) are magnetic sensors.

21. Steering device according to claim 20, characterized in that the magnetic sensors are arranged in lines for reading a multi-bit code, in particular an 8-bit code.

22. Steering device according to claim 20 or claim 21, characterized in that the sensor (35) has a reading head with pole structures which are arranged on a circular arc adapted to the diameter of the steering shaft (20).

23. A method for producing a steering device according to one of the preceding claims, characterized in that the microstructures on the steering shaft (20) or the device non-positively connected to the steering shaft are produced using thin-film techniques and that the structuring is done using photolithographic techniques he follows.

24. The method according to claim 23, characterized in that the thin-film technology is a PVD and/or CVD technology.

25. The method according to claim 23 or 24, characterized in that the microstructures are formed by a dry etching process and / or wet chemical etching process.

26. A method for producing a steering device according to one of claims 1 to 22, characterized in that the microstructures are produced using a laser beam technology.

27. The method according to claim 26, characterized in that the laser beam technology used is a direct-writing laser ablation process and/or a laser lithographic process and/or a direct-acting mask-related laser structuring process.